pinctrl: pinconf-generic: add generic APIs for mapping pinctrl node

Add generic APIs to map the DT node and its sub node in pinconf generic
driver. These APIs can be used from driver to parse the DT node who
uses the pinconf generic APIs for defining their nodes.

Changes from V1:
- Add generic property for pins and functions in pinconf-generic.
- Add APIs to map the DT and subnode.
- Move common utils APIs to the pinctrl-utils from this file.
- Update the binding document accordingly.
Changes from V2:
- Rebased the pinctrl binding doc on top of Stephen's cleanup.
- Rename properties "pinctrl-pins" and "pinctrl-function" to
  "pins" and "function".

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinconf-generic.c

@@ -24,6 +24,7 @@
 #include <linux/of.h>
 #include "core.h"
 #include "pinconf.h"
+#include "pinctrl-utils.h"
 
 #ifdef CONFIG_DEBUG_FS
 
@@ -236,4 +237,99 @@ out:
 	kfree(cfg);
 	return ret;
 }
+
+int pinconf_generic_dt_subnode_to_map(struct pinctrl_dev *pctldev,
+		struct device_node *np, struct pinctrl_map **map,
+		unsigned *reserved_maps, unsigned *num_maps)
+{
+	int ret;
+	const char *function;
+	struct device *dev = pctldev->dev;
+	unsigned long *configs = NULL;
+	unsigned num_configs = 0;
+	unsigned reserve;
+	struct property *prop;
+	const char *group;
+
+	ret = of_property_read_string(np, "function", &function);
+	if (ret < 0) {
+		/* EINVAL=missing, which is fine since it's optional */
+		if (ret != -EINVAL)
+			dev_err(dev,
+				"could not parse property ti,function\n");
+		function = NULL;
+	}
+
+	ret = pinconf_generic_parse_dt_config(np, &configs, &num_configs);
+	if (ret < 0) {
+		dev_err(dev, "could not parse node property\n");
+		return ret;
+	}
+
+	reserve = 0;
+	if (function != NULL)
+		reserve++;
+	if (num_configs)
+		reserve++;
+	ret = of_property_count_strings(np, "pins");
+	if (ret < 0) {
+		dev_err(dev, "could not parse property ti,pins\n");
+		goto exit;
+	}
+	reserve *= ret;
+
+	ret = pinctrl_utils_reserve_map(pctldev, map, reserved_maps,
+			num_maps, reserve);
+	if (ret < 0)
+		goto exit;
+
+	of_property_for_each_string(np, "pins", prop, group) {
+		if (function) {
+			ret = pinctrl_utils_add_map_mux(pctldev, map,
+					reserved_maps, num_maps, group,
+					function);
+			if (ret < 0)
+				goto exit;
+		}
+
+		if (num_configs) {
+			ret = pinctrl_utils_add_map_configs(pctldev, map,
+					reserved_maps, num_maps, group, configs,
+					num_configs, PIN_MAP_TYPE_CONFIGS_PIN);
+			if (ret < 0)
+				goto exit;
+		}
+	}
+	ret = 0;
+
+exit:
+	kfree(configs);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pinconf_generic_dt_subnode_to_map);
+
+int pinconf_generic_dt_node_to_map(struct pinctrl_dev *pctldev,
+		struct device_node *np_config, struct pinctrl_map **map,
+		unsigned *num_maps)
+{
+	unsigned reserved_maps;
+	struct device_node *np;
+	int ret;
+
+	reserved_maps = 0;
+	*map = NULL;
+	*num_maps = 0;
+
+	for_each_child_of_node(np_config, np) {
+		ret = pinconf_generic_dt_subnode_to_map(pctldev, np, map,
+						&reserved_maps, num_maps);
+		if (ret < 0) {
+			pinctrl_utils_dt_free_map(pctldev, *map, *num_maps);
+			return ret;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pinconf_generic_dt_node_to_map);
+
 #endif

include/linux/pinctrl/pinconf-generic.h

@@ -137,6 +137,12 @@ static inline unsigned long pinconf_to_config_packed(enum pin_config_param param
 	return PIN_CONF_PACKED(param, argument);
 }
 
+int pinconf_generic_dt_subnode_to_map(struct pinctrl_dev *pctldev,
+		struct device_node *np, struct pinctrl_map **map,
+		unsigned *reserved_maps, unsigned *num_maps);
+int pinconf_generic_dt_node_to_map(struct pinctrl_dev *pctldev,
+		struct device_node *np_config, struct pinctrl_map **map,
+		unsigned *num_maps);
 #endif /* CONFIG_GENERIC_PINCONF */
 
 #endif /* __LINUX_PINCTRL_PINCONF_GENERIC_H */